1. Field of the Invention
This application relates broadly to a fiber optic sight for firearms. More particularly, it concerns an improved form of a fiber optic sight with nighttime capabilities for use with firearms, including handguns and long arms.
2. Description of the Prior Art
Co-pending U.S. patent application Ser. No. 11/899,069 filed Sep. 5, 2007, “Fiber Optic Sight for Firearms”, is hereinto incorporated as a reference for this current application. There are many fiber optic sights available which utilize tritium inserts for illumination during nighttime operations but there are a number of problems with such sights. Generally there have been four methods of dealing with the light emitted from a tritium night insert. The first is to put the tritium insert at the distal end of the fiber in which case the light emitted from the tritium vial must travel thru the full length of the fiber. An example of this method is disclosed in U.S. 2007/0107292 (Bar Yona et al). The second method is to put the tritium so it shines onto the outside surface of the fiber optic rod from which some percentage is absorbed by the rod and transmitted to the shooters eye. An example of this method is disclosed in U.S. Pat. No. 6,581,317 (Slates). The third method is to position a tritium insert adjacent to the fiber optic where it is not co-located with the fiber optic rod. This method is disclosed in U.S. Pat. No. 6,216,351 (Flubacher, et al). The fourth method is to have the tritium insert inserted into a fiber optic rod from the front and to have the output face of the tritium insert coplanar with the face of the fiber optic rod. This method is disclosed in U.S. Pat. No. 6,233,836 (Uhlmann et al). As a result, the manufacturers of sights of types one and two typically end up using tritium inserts that have higher output power (more radiation) than do sights of types three and four with direct viewing of the tritium insert. Obviously, what is desired is a sight with co-located day and night light viewing in a shorter, brighter package that still utilizes lower power tritium inserts (less radiation) and also minimizes sight length so to maximize the distance between the front and rear sight for improved accuracy.
The present invention solves these issues by providing a fiber optic sight that provides for co-located day and night sight views with increased illumination during the day, uses a low power tritium insert for night time use and packages it all in a relatively small volume. This is achieved by placing a tritium insert into a cavity within a fiber optic rod that is angled at its forward end which allows ambient light from the exterior of the rod opposite the angled cut to reflect off the angled cut toward the shooters eyes. At night the tritium insert has enough length of fiber optic rod to shine thru to achieve a nice transition from bright ring during the day to a small central dot at night while maintaining the same color light for both. The single flat proximal surface of the rod is easy to keep clean and the tritium insert can still be of low radiation. An optical grade epoxy optically couples the tritium insert output lens to the fiber optic rod so to minimize light loss from the tritium insert into the fiber optic rod.